High performance laser mirrors adapted for use with high power laser beams are subject to severe thermal gradients resulting from the absorption of a portion of the high power beam at the reflective surface of the mirror. The thermal gradients can result in distortion of the mirror with a corresponding distortion in the wave front of the radiation reflected from the reflective surface. One method known in the art for minimizing thermal distortion within mirrors is to flow a coolant through the mirror in heat exchange relationship with the mirror. Typically, either the faceplate of the mirror or the mirror substrate is cooled to minimize the temperature variations within the mirror. Attempts have also been made at selecting particular layered materials which compensate for thermal distortions. U.S. Pat. No. 3,609,589 teaches a materials-compensating approach for correcting thermal distortions. There have been many varieties of coolant flow, heat exchange systems for minimizing thermal distortions. Note U.S. Pat. Nos. 3,637,296; 3,645,608; 3,836,236; 3,854,799; 3,854,800; 3,926,510; 3,942,880; 4,006,972; 4,006,973 and 4,175,834. However, even such cooled laser mirrors while improving the performance of the laser mirrors leave much room for improvement.